docs: polish README wording and fix inaccurate comments

[mevinagrise]

This PR improves a few small wording and accuracy issues in the documentation and comments.

Specific changes include:

• Changed To init the allocator: to To initialize the allocator: in README.md.
• Corrected the wording in the license acknowledgement and fixed the phil-opp spelling.
• Updated the doc comment on LockedFrameAllocator::new to say Creates an empty frame allocator. instead of Creates an empty heap.

Why this is useful:

• It improves documentation clarity without changing behavior.
• It fixes a misleading comment in the FrameAllocator API.
• It keeps the PR tightly scoped and easy to review.

Testing:

• Ran cargo test.
• Ran cargo test --doc.

[Copilot]

Pull request overview

This PR polishes documentation and inline Rust doc comments to improve clarity and correctness without changing runtime behavior.

Changes:

• Updated LockedFrameAllocator::new doc comment to correctly describe creating an empty frame allocator.
• Improved README wording for allocator initialization instructions.
• Refined README license acknowledgement wording and corrected the phil-opp spelling.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/frame.rs	Fixes an inaccurate doc comment for LockedFrameAllocator::new.
README.md	Clarifies initialization wording and improves license acknowledgement text.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.